Learning from the land; Grand Staircase-Escalante National Monument Science Symposium proceedings November 4-5, 1997, Southern Utah University - Softcover

Koselak, Janine J.

Softcover

ISBN 10: 1236206207 ISBN 13: 9781236206206

Verlag: RareBooksClub.com, 2012

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1997* Excerpt: ...These rocks are, over much of their areal extent, lithified sand dunes. The structure and shape of the preserved dunes are still visible. The weathering characteristics of these ancient dunes create much of the aesthetic beauty of the canyon country's harmonious arched landforms. Fluvially deposited rocks, which are generally finer grained and less transmissive than the courser grained sandstones above them, underlie the Wingate and the Navajo, as well as the Entrada in some places. This pairing of a courser grained, sandy unit (facies) above a finer grained facies of siltstones, claystones, and mudstones creates an aquifer-aquitard couplet. While such a contact commonly occurs between formally identified rock formations, the relationship between coursegrained and fine-grained facies also commonly occurs within an individual rock formation. Ground water moves downward through the more transmissive facies and is stopped when it reaches the less-permeable, fine-grained facies. Then it spreads laterally until it reaches another vertical conduit: a fault, joint, fracture, or the side of a canyon wall that has exposed the aquifer-aquitard contact. These simple controls on the movement of ground water, along with larger scale controls like the dip (angle relative to horizontal) of the rock unit itself, determine whether and where water will exit the aquifer as seeps and springs. Springs are point-source water delivery phenomena, and create a fluvial (streaming) regime beneath them, however small or large they may be. Moving water is both an erosional and a depositional force. It entrains particles of the rock and soil it moves over and carries them some distance before dropping its bedload as an alluvial deposit. Seeps, however, generally do not have a significa...

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• Verlag: RareBooksClub.com
• Erscheinungsdatum: 2012
• ISBN 10: 1236206207
• ISBN 13: 9781236206206
• Einband: Tapa blanda
• Anzahl der Seiten: 244